1. Field of the Invention
This invention is generally directed to locking devices for trailer or towing hitches and specifically to a trailer hitch lock assembly which completely surrounds the socket end portion of the trailer hitch and is securely retained in interlocking relationship thereto to thereby prevent unauthorized use of or access to the trailer hitch socket.
2. History of the Art
There currently exists a substantial problem with the theft and unauthorized use of towed vehicles including boat trailers, storage or moving trailers and livestock or farm trailers. Many of these towed vehicles are connected to a towing vehicle by means of a hitch bar which includes a socket member which is selectively seated during use around a ball carried by the tow bar of the towing vehicle.
In previous attempts to discourage the theft of trailers having socket type hitches, various types of locks and theft prevention devices have been used to obstruct or otherwise make it difficult to utilize the socket of the trailer towing hitch. In U.S. Pat. No. 3,237,969 to Geresy, two types of hitch locks are disclosed. In the first embodiment, a plate is fitted around a rim projecting from the socket portion of the trailer hitch and extends across the opening into the hitch socket. A hinged plate is locked to the first plate in order to anchor the lock in place. In the second embodiment, a ball member is retained in the trailer hitch socket by a lock or lock and pin assembly which is mounted through aligned openings made through the trailor tongue adjacent the hitch socket.
In the foregoing prior art locks, the locking member such as a padlock is exposed exteriorly of the locking assembly and thus may be easily tampered with by someone desiring to dismantle or remove the assembly. In addition, the ball retaining lock requires that some modification be made to the trailer towing hitch in order to accommodate the locking pins associated with the lock. Other prior art trailer locking devices having exteriorly exposed locking members include U.S. Pat. Nos. 3,434,741 to Grant, Jr.; 3,884,045 to Vuillemot; and 4,032,171 to Allen et al.
Another form of trailer hitch lock is disclosed in U.S. Pat. No. 4,141,569 to Dilk. This lock includes a frame having a post mounted thereto which is inserted into the socket of the trailer hitch. A cover is hingedly mounted to the frame and includes a second post which extends downwardly to a point adjacent the top of the socket portion of the trailer hitch when the lock is positioned on the hitch. A keeper and a hasp are disposed within a partially enclosed housing connected adjacent to the main frame and are secured by a conventional padlock. This type of lock is somewhat structurally complicated and is only as strong as the hinge element which connects the frame to the closure or cover of the lock assembly.